US10080261B2 - Insulated structure of induction heating coil - Google Patents

Insulated structure of induction heating coil Download PDF

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US10080261B2
US10080261B2 US12/733,922 US73392208A US10080261B2 US 10080261 B2 US10080261 B2 US 10080261B2 US 73392208 A US73392208 A US 73392208A US 10080261 B2 US10080261 B2 US 10080261B2
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ceramic
induction heating
heating coil
cloth
fibers
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US20100243644A1 (en
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Hidetoshi Terashima
Seiji Ieda
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Nippon Steel Corp
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Nippon Steel and Sumitomo Metal Corp
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/36—Coil arrangements
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/06—Surface hardening
    • C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
    • C21D1/10—Surface hardening by direct application of electrical or wave energy; by particle radiation by electric induction
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/34—Methods of heating
    • C21D1/42—Induction heating
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/56—Continuous furnaces for strip or wire
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/56—Continuous furnaces for strip or wire
    • C21D9/60—Continuous furnaces for strip or wire with induction heating
    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
    • D03D15/00—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used
    • D03D15/12—
    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
    • D03D15/00—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used
    • D03D15/20—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used characterised by the material of the fibres or filaments constituting the yarns or threads
    • D03D15/242—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used characterised by the material of the fibres or filaments constituting the yarns or threads inorganic, e.g. basalt
    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
    • D03D15/00—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used
    • D03D15/50—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used characterised by the properties of the yarns or threads
    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
    • D03D15/00—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used
    • D03D15/50—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used characterised by the properties of the yarns or threads
    • D03D15/513—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used characterised by the properties of the yarns or threads heat-resistant or fireproof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D11/00—Arrangement of elements for electric heating in or on furnaces
    • F27D11/12—Arrangement of elements for electric heating in or on furnaces with electromagnetic fields acting directly on the material being heated
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D99/00—Subject matter not provided for in other groups of this subclass
    • F27D99/0001—Heating elements or systems
    • F27D99/0006—Electric heating elements or system
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • D—TEXTILES; PAPER
    • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B2101/00—Inorganic fibres
    • D10B2101/02—Inorganic fibres based on oxides or oxide ceramics, e.g. silicates
    • D10B2101/08—Ceramic
    • D—TEXTILES; PAPER
    • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B2505/00—Industrial
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D99/00—Subject matter not provided for in other groups of this subclass
    • F27D99/0001—Heating elements or systems
    • F27D99/0006—Electric heating elements or system
    • F27D2099/0015—Induction heating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency
    • Y02P10/253—

Definitions

  • the present invention relates to an insulated structure of an induction heating coil used for continuous heating of a running steel sheet.
  • the continuous annealing furnace of a steel sheet, the alloying furnace of a plating facility for steel sheet, and other steel sheet production facilities use induction heating coils for rapidly heating the steel sheets.
  • Such an induction heating coil is made a tubular coil conductor provided with a steel sheet passage inside it (solenoid type), a coil conductor set so as to sandwich the sheet from above and below (traverse type), etc. to enable uniform heating of the steel sheet from the front and back surfaces and is covered on its surface with an insulating material having heat resistance.
  • JP2005-156124 A unlike the present invention, relates to an induction heating coil of a hot forged material and discloses an insulated structure made of monolithic refractory containing a porous flame resistant aggregate and covering the inside surface of the induction heating coil.
  • JP2006-169603 A discloses an induction heating coil for the same application of the present invention insulated by an alumina ceramic. However, it does not describe details of the alumina ceramic.
  • Such a conventional insulated structure of an induction heating coil was selected focusing solely on the heat resistance and insulation ability. It was learned that it was not possible to prevent a drop in insulation due to entry of fine metal particles in the atmosphere (for example, zinc fumes).
  • surfaces of the coil wires may also be coated in advance with a varnish, enamel, or other insulating coating. Further, if the temperature inside the furnace exceeds 450° C., these insulating coatings are burned off and the surfaces of the copper wires end up being exposed. For this reason, if zinc fumes enter, it is not possible to prevent a drop in insulation of the induction heating coil.
  • An object of the present invention is to solve the above conventional problem and provide an insulated structure of an induction heating coil continuously heating a running steel sheet which maintains insulation characteristics equal to or better than at the start under continuous usage conditions of a high temperature of several hundred degrees centigrade and further prevents a drop in insulation due to zinc fumes and other fine metal particles and thereby extends the service life of the induction heating coil.
  • the aspect of the invention of the present claim 1 is an induction heating coil for induction heating of steel sheet characterized by covering the surface on the side facing the steel sheet by a ceramic cloth and forming a heat-resistant insulation layer made of a surface hardening ceramic material containing ceramic short-fibers on one or both of an induction coil side or a steel sheet side of the ceramic cloth.
  • the induction heating coil may be made a solenoid type.
  • the ceramic cloth is made of silica or alumina-silica ceramic long-fibers not containing boron.
  • the surface hardening ceramic material includes alumina or alumina-silica fine particles, alumina-silica ceramic short-fibers, colloidal silica, and an organic binder.
  • the ceramic short-fibers are obtained by fiberized from a ceramic fiber bulk.
  • the surface hardening ceramic material is spray coated on the surface of the ceramic cloth to form a heat-resistant insulation layer.
  • the induction heating coil can be installed in a continuous annealing furnace of steel sheet or an alloying furnace of a plating facility.
  • the surface of the side of the induction heating coil facing the steel sheet is covered by ceramic cloth and the induction coil side and/or steel sheet side of the ceramic cloth is formed with a heat-resistant insulation layer made of a surface hardening ceramic material containing ceramic short-fibers.
  • the heat-resistant insulation layer of the present invention is comprised of a ceramic cloth superior in heat resistance and insulation ability and a surface hardening ceramic material including ceramic short-fibers, so can exhibit stable heat resistance and insulation ability over a long period of time even under high temperature conditions of 500° C. to 1200° C.
  • the induction heating coil for the induction heating of the steel sheet is a solenoid type, it is sufficient to make at least just the inner circumference facing the steel sheet this structure. This is because the zinc fumes and other fine metal particles are present inside the furnace through which the steel sheet is run. Needless to say both the inner and outer circumferences of the induction heating coil may also be covered by this heat-resistant insulation layer.
  • the ceramic cloth As set forth in claim 3 , if making the ceramic cloth from silica or alumina-silica ceramic long-fibers not containing boron, at the time of heating, boron will not elute and diffuse to and permeate the inside of the surrounding ceramic cloth and cause deterioration, and stable heat resistance and insulation ability can be exhibited.
  • the practical heat-resistant temperature of these ceramic cloths is, with silica, 800° C. or more, and, with alumina-silica, 1000° C. or more. They can also be used for a high temperature induction heating apparatus able to heat to 800° C. or more.
  • the surface hardening ceramic material is one including alumina or alumina-silica fine particles, alumina-silica ceramic short-fibers, and colloidal silica, it is possible to exhibit stable heat resistance and insulation ability.
  • ceramic particles and ceramic short-fibers are the same in material, the adhesiveness between them is good and it is possible to enhance the effect of prevention of passage of fine metal particles.
  • the ceramic short-fibers are obtained by fiberized from a ceramic fiber bulk, it is possible to lower the production costs.
  • the coating work efficiency is good and a broad area can be coated with a uniform thickness.
  • FIGS. 1( a ), ( b ), ( c ) are center cross-sectional views of an induction heating coil in the present embodiment.
  • FIG. 2 is an explanatory view showing the state of sealing a mesh of ceramic cloth by ceramic short-fibers and ceramic particles.
  • FIG. 3 is an explanatory view of a device used for the withstand voltage test.
  • FIG. 4 is a comparative view of the state of insulation between the coil and frame of the present invention and a prior art product at 400° C.
  • FIGS. 1( a ), ( b ), ( c ) are center cross-sectional views of an induction heating coil 1 in examples of the present embodiment.
  • FIG. 1( a ) shows the case of a ceramic cloth 4 on the steel sheet side of which a heat-resistant insulation layer made of a surface hardening ceramic material 7 including ceramic short-fibers is formed.
  • FIG. 1( b ) shows the case of a ceramic cloth 4 on the coil side of which a heat-resistant insulation layer made of a surface hardening ceramic material 7 is formed.
  • FIG. 1( c ) shows the case of a ceramic cloth 4 on both the steel sheet side and coil side of which heat-resistant insulation layers made of a surface hardening ceramic material 7 are formed.
  • the induction heating coil 1 is comprised of a coil conductor 1 a and a coil frame 1 b and is supported by a base 2 .
  • the induction heating coil 1 is a solenoid type provided at its center with a steel sheet passage 3 through which a steel sheet S passes vertically. Further, this may also be placed horizontally to enable horizontal sheet passage.
  • FIG. 1( a ) will be used to explain the present invention.
  • the surface of the side of this induction heating coil 1 facing the steel sheet S that is, the surface near the steel sheet passage 3 , is covered by a heat-resistant insulation layer comprised of a ceramic cloth 4 and surface hardening ceramic material 7 . That is, at the surface of the induction heating coil 1 near the steel sheet passage 3 , the ceramic cloth 4 is fastened by fasteners 5 and 6 .
  • the center part of this ceramic cloth 4 is preferably bonded to the coil frame 1 b using a sealant. Further, the surface of this ceramic cloth 4 is sprayed with a surface hardening ceramic material 7 to be coated to a uniform thickness.
  • Ceramic cloth 4 has conventionally been used for insulating induction heating coils.
  • silica and alumina-silica types there are silica and alumina-silica types.
  • silica type for example, there is the N-Silica Fiber (maximum heat-resistant temperature 1000° C.) made by Nihon Glass Fiber Industrial Co., Ltd.
  • alumina-silica type for example, there is TOMBO No. 8350 Rubilon made by Nichias.
  • a woven fabric of alumina-silica ceramic long-fibers superior in heat resistance and insulation ability is preferably used.
  • Most preferable from the viewpoint of the heat resistance is a composition of alumina in 70 to 80% and silica in 30 to 20%. Note that this composition preferably does not include any boron. This is because boron elutes at a high temperature and is liable to cause the ceramic fibers to degrade.
  • the “long-fibers” are comprised of extremely fine ceramic fibers mainly made of alumina, silica, etc. and having a diameter of several ⁇ m to 10 ⁇ m or so twisted together.
  • ceramic fibers in the case of alumina, of 5 to 10 cm in length or, in the case of silica, of 50 cm or more in length, able to be woven to obtain a ceramic cloth.
  • the ceramic cloth 4 there are various ways to weave the ceramic cloth 4 such as a plain weave, twill weave, satin weave, etc., but in the present invention, no difference in action or effect due to the weaving method can be recognized, so any weaving method may be used. Further, the thickness may be 0.3 to 1.2 mm or so.
  • the ultrahigh temperature heat-resistant fibers commercially available from Nihon Glass Fiber Industrial Co., Ltd. under the name of “Alumina Seven” (maximum heat-resistant temperature: 1200° C.) may be used.
  • the surface is coated with a surface hardening ceramic material 7 including ceramic short-fibers.
  • This surface hardening ceramic material 7 includes alumina or alumina-silica fine particles, alumina-silica ceramic short-fibers, colloidal silica, and an organic binder.
  • the “alumina-silica composition” means one containing alumina in a mass % of 40 to 95% and silica in 60 to 5%.
  • the fine particles have a size of a circle equivalent diameter of 0.1 to 50 ⁇ m or so.
  • the ceramic short-fibers ones having a diameter of several ⁇ m to 10 ⁇ m or so and a length of several ⁇ m to 500 ⁇ m or so obtained by fiberized from a bulk are preferably used.
  • the “bulk” means the wadding shaped product after removal of spherical particles (generally called “shot”) not used for forming fibers in the process of forming fibers by melt processing of the alumina, silica, and other materials.
  • shots spherical particles
  • an organic binder a cellulose-based glue may be used as an organic binder.
  • a surface hardening ceramic material 7 for example, the one commercially available from Shinnikka Thermal Ceramics Corporation under the name “Thermopreg” may be used.
  • This surface hardening ceramic material 7 is a product aimed at hardening the surface of the ceramic fibers and preventing flying fibers and is provided with a heat resistance of a maximum usage temperature reaching 1400° C.
  • the ceramic short-fibers 8 entangle with the mesh of the ceramic cloth 4 . Furthermore, the ceramic particles 9 also deposit on this to reliably plug the mesh of the ceramic cloth 4 . These are all the same materials, so the adhesiveness is also good. Therefore, after curing for hardening, entry of zinc fumes and other fine metal particles can be completely prevented. Note that this coating can be performed by spraying by a spray gun, so even when the induction heating coil 1 is tubular, easy coating to the inside becomes possible.
  • the surface hardening ceramic material 7 has the same effect whether, as shown in FIGS. 1( a ), ( b ), and ( c ) , coated on the steel sheet side of the ceramic cloth 4 or the induction coil side of the ceramic cloth 4 . Either may be selected depending on the convenience for installation. It is more preferable to coat this on both the induction coil side and steel sheet side needless to say.
  • the conventionally used high temperature heat-resistant coatings for example “Pyrocoat” made by Otake Ceram etc.
  • ceramic binders for example “Thermodyne” made by Shinnikka Thermal Ceramics Corporation etc.
  • an induction heating coil of the present invention it is possible to completely cover the surface of the induction heating coil 1 facing the steel sheet passage 3 by the ceramic cloth 4 and surface hardening ceramic material 7 and insulate and protect the induction heating coil under conditions of a usage temperature of several hundred to 400° C. Furthermore, it is possible to completely prevent the entry of zinc fumes and other floating fine metal particles into the steel sheet passage 3 and prevent a drop in the insulation ability. For this reason, it is possible to reliably prevent line stoppages due to a drop in insulation of the induction heating coil 1 .
  • the induction heating coil according to the present invention maintained an insulation resistance of 7 M ⁇ even after 3 months after installation.
  • the surface hardening ceramic material “Thermopreg” used in the present invention and the ceramic binder “Thermodyne” of the same chemical composition, but not containing any short-fibers were used to compare the coating performances on cooled copper sheet and alumina cloth (the above-mentioned “Alumina Seven”).
  • “Thermodyne” is a product of Shinnikka Thermal Ceramics Corporation the same as “Thermopreg”. Both have chemical compositions of alumina+silica of 95% or more and maximum usage temperatures of 1400° C.
  • test pieces The surfaces of 100 mm ⁇ 100 mm water-cooled copper sheets were coated with “Thermopreg” and “Thermodyne” by brushing to thicknesses of about 1.5 mm and cured to prepare two types of test pieces. These test pieces were placed in an electric furnace held at 650° C. and heated for 20 minutes while being cooled by running 3 liter/min of cooling water, then were forced cooled indoors for 20 minutes. This operation was repeated five times then the state of occurrence of cracks and detachment at the surface of the test pieces was confirmed visually.
  • test piece where “Thermodyne” was coated on the surface of the water-cooled copper sheet already suffered from numerous fine cracks at the stage of the end of curing and suffered from partial blistering and peeling due to the first heating and cooling.
  • test piece where “Thermopreg” was coated on the surface of the water-cooled copper sheet had no cracks or peeling at all at the stage of the end of curing and did not exhibit any cracks or peeling even after five repeated heating and cooling operations.
  • test pieces were coated by brushing with “Thermopreg” and “Thermodyne” to thicknesses of about 1.5 mm and cured to prepare two types of test pieces. These test pieces were placed in an electric furnace held at 650° C. and heated for 20 minutes, then were forced cooled indoors for 20 minutes. This operation was repeated five times. The state of occurrence of cracks and detachment was visually checked.
  • test piece where “Thermodyne” was coated on the surface of the alumina cloth already suffered from numerous fine cracks at the stage of the end of curing and suffered from partial blistering due to the first heating and cooling.
  • test piece where “Thermopreg” was coated had no cracks or peeling at all at the stage of the end of curing of course and even after five repeated heating and cooling operations.
  • “Thermopreg” containing short-fibers was good in adhesiveness both with copper sheet and with alumina cloth and furthermore did not allow cracks or peeling even with repeated heating and cooling, so the entry of zinc fumes and other fine metal particles can be effectively prevented.
  • test pieces for the withstand voltage test four types were prepared: copper sheets coated on their surfaces with only “Thermopreg”, copper sheets covered on their surfaces with alumina cloth and “Thermopreg”, copper sheets coated on their surfaces with only “Thermodyne”, and copper sheets covered on their surfaces with alumina cloth and “Thermodyne”.
  • test piece 11 was attached to the front end of the voltage electrode 10 , a ground electrode 12 made of a copper sheet was brought into contact with its surface, and current flowing to the ground electrode 12 was detected while gradually raising the AC voltage applied to the voltage electrode 10 so as to test the withstand voltage performance of the four types of test pieces 11 .
  • the power source was the commercial power supply. This was boosted to 2000V for use. Note that the test conditions were a temperature of 24° C. and a humidity of 52%.
  • the test piece where only “Thermopreg” was coated on the surface of the copper sheet rapidly rose in charging current near 1000V and suffered from insulation breakdown.
  • the invention product with alumina cloth and “Thermopreg” covered on the surface of the copper sheet had a charging current of about 7 mA even when boosted to 2000V, had a stable current value during the test, and exhibited a sufficient withstand voltage characteristic.
  • the test piece with only “Thermodyne” coated on the surface of the copper sheet suffered from insulation breakdown at 1300V.
  • test piece with alumina cloth and “Thermodyne” covered on the surface of the copper sheet had a charging current when boosted to 2000V of about 20 mA and a current value during the test fluctuating in the range of 4 to 17 mA or somewhat unstable.
  • the resistance values at 1000V were, in the above order, 10 M ⁇ , 13% ⁇ , 27 M ⁇ , and 40 M ⁇ . From the results, from the overall perspective, the best withstand voltage characteristic was exhibited by the combination of an alumina cloth and “Thermopreg”.
  • alumina cloth coated with “Thermodyne” and alumina cloth coated with “Thermopreg” were stacked in two layers and tested for withstand voltage by a method similar to the above, whereby the charging current was 8.3 mA even at 2700V or a good withstand voltage characteristic was exhibited. Note that the test conditions were a temperature of 26° C. and a humidity of 4.6%.
  • the voltage was similarly boosted to 2700V in the state with zinc fumes scattered over the top surface of the test piece, whereby the charging current rose to 12 mA, but it was confirmed there were no unstable points even during the test and superior withstand voltage characteristics were exhibited even in the presence of zinc fumes.
  • the silica, boron-containing alumina-silica, boron-free alumina-silica ceramic cloths applying the present invention were adhered to water-cooled copper sheets of a grade similar to the induction coil and were further coated with Thermopreg, heated at 500 to 1200° C. ⁇ 72 Hr, and evaluated for insulation ability and strength. The results are shown in Table 1.
  • the insulation was evaluated by an apparatus similar to the above Experiment 2.
  • the insulation was evaluated as “Good”, while when the withstand voltage characteristic was poor and insulation breakdown occurred, it was evaluated as “Poor” as shown in Table 1.
  • the strength was evaluated by observing whether the ceramic cloths attached to the water-cooled copper sheets sagged during high temperature treatment or other problems occurred. When the state could be maintained, the strength was evaluated as “Good” and when the state could not be maintained, the strength was evaluated as “Poor” in Table 1.
  • each material exhibited a good insulation ability and strength up to 600° C. Further, silica exhibited a drop in strength a 800° C. and insulation breakage at 1000° C. Boron-containing alumina-silica also exhibited a drop in strength at 1000° C. On the other hand, even in boron-free alumina-silica, it was confirmed that there was no drop in strength and a good insulation ability was maintained even at 1200° C.
  • the insulated structure according to the present invention for an induction heating coil, it is possible to maintain insulation characteristics equal to or better than at the start and prevent a drop in insulation due to the entry of zinc fumes and other fine metal particles even under continuous usage conditions of a high temperature of hundreds of degrees centigrade. As a result, it is possible to extend the service life of the induction heating coil.
  • the invention is not limited to steel sheet.
  • an induction heat coil of other metal materials similar effects can be expected. This is technology able to be applied to not only the ferrous metal industry, but the broader industrial world and has much to contribute to.

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  • Textile Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Inorganic Chemistry (AREA)
  • General Induction Heating (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
  • Woven Fabrics (AREA)
  • Laminated Bodies (AREA)
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JP2007251083 2007-09-27
JP2007-251083 2007-09-27
JP2008213937A JP4332203B2 (ja) 2007-09-27 2008-08-22 誘導加熱コイルの絶縁構造
JP2008-213937 2008-08-22
PCT/JP2008/067992 WO2009041729A1 (ja) 2007-09-27 2008-09-26 誘導加熱コイルの絶縁構造

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Families Citing this family (7)

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WO2013164840A2 (en) * 2012-03-09 2013-11-07 Yadav Ganapati Dadasaheb Chemical Engineering Department, Institute Of Chemical Technology System and method for production of membrane
JP5950092B2 (ja) * 2012-04-16 2016-07-13 Ｊｆｅスチール株式会社 連続焼鈍炉
WO2014035480A1 (en) * 2012-08-30 2014-03-06 General Electric Company Induction furnace with uniform cooling capability
RU2544724C2 (ru) * 2013-03-21 2015-03-20 Открытое акционерное общество "Завод им. В.А. Дегтярева" Печь шахтная
US20160290680A1 (en) * 2015-03-30 2016-10-06 Stellar Generation, Inc. Ultra High Temperature Solar-Driven Gas Heating System
US11317481B2 (en) * 2016-12-08 2022-04-26 Koyo Thermo Systems Co., Ltd. Supporting structure for induction heating coil, and induction heating device
RU174244U1 (ru) * 2017-02-21 2017-10-09 Михаил Васильевич Пилягин Устройство для термообработки металлических изделий в воздушной среде в муфеле

Citations (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3705253A (en) * 1971-09-02 1972-12-05 Wilson Eng Co Inc Lee Furnace wall construction
JPS5027646Y1 (zh) 1970-12-03 1975-08-16
JPS5332550B2 (zh) 1973-08-29 1978-09-08
JPS5460334A (en) 1978-09-18 1979-05-15 Kumiai Chem Ind Co Ltd Granular base material for construction
US4221672A (en) * 1978-02-13 1980-09-09 Micropore International Limited Thermal insulation containing silica aerogel and alumina
EP0057252A2 (de) * 1981-01-29 1982-08-11 Grünzweig + Hartmann und Glasfaser AG Vorrichtung zur wärmedämmenden Lagerung einer elektrischen Heizwendel, insbesondere für eine strahlungsbeheizte Kochplatte, sowie Wärmedämmplatte hierzu und Verfahren zu ihrer Herstellung
JPS6399795A (ja) 1986-10-15 1988-05-02 Hitachi Ltd ブラシレスモ−タの位置検出回路
JPH05335068A (ja) 1992-05-28 1993-12-17 Nippon Steel Corp 誘導加熱用発振コイルの断熱材
US5416795A (en) * 1994-05-20 1995-05-16 Kaniuk; John A. Quick change crucible for vacuum melting furnace
JPH088051A (ja) 1994-06-17 1996-01-12 Nkk Corp 金属板の誘導加熱方法及び装置
JPH08288057A (ja) 1995-04-12 1996-11-01 Meidensha Corp 誘導加熱装置
EP0822733A1 (fr) 1996-08-02 1998-02-04 Selas SA Dispositif de chauffage par induction et installation de traitement thermique en continu comportant un tel dispositif
US6114675A (en) * 1997-12-05 2000-09-05 Mitsubishi Heavy Industries, Ltd. Alloying system and heating control device for high grade galvanized steel sheet
US20020168554A1 (en) * 2000-05-19 2002-11-14 Taijiro Matsui Heat insulating material having high durability, method for producing the same, use of the same, and method for applying the same
JP2005156124A (ja) 2003-11-21 2005-06-16 Hagoromo Denki Kk 誘導加熱用加熱コイルの耐熱内壁
JP2005221132A (ja) * 2004-02-05 2005-08-18 Nippon Steel Corp 誘導加熱炉の炉壁構造
JP2006169603A (ja) 2004-12-17 2006-06-29 Jfe Steel Kk 加熱設備及び加熱方法
JP2008060026A (ja) 2006-09-04 2008-03-13 Nippon Steel Corp 炉内設置型誘導加熱装置

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5460334U (zh) * 1977-10-06 1979-04-26
JPH0515753Y2 (zh) * 1986-12-19 1993-04-26
JPH0166786U (zh) * 1987-10-22 1989-04-28
JP3942261B2 (ja) * 1998-02-13 2007-07-11 電気興業株式会社 誘導加熱コイル及びこの誘導加熱コイルを用いた誘導加熱装置

Patent Citations (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5027646Y1 (zh) 1970-12-03 1975-08-16
US3705253A (en) * 1971-09-02 1972-12-05 Wilson Eng Co Inc Lee Furnace wall construction
JPS5332550B2 (zh) 1973-08-29 1978-09-08
US4221672A (en) * 1978-02-13 1980-09-09 Micropore International Limited Thermal insulation containing silica aerogel and alumina
JPS5460334A (en) 1978-09-18 1979-05-15 Kumiai Chem Ind Co Ltd Granular base material for construction
EP0057252A2 (de) * 1981-01-29 1982-08-11 Grünzweig + Hartmann und Glasfaser AG Vorrichtung zur wärmedämmenden Lagerung einer elektrischen Heizwendel, insbesondere für eine strahlungsbeheizte Kochplatte, sowie Wärmedämmplatte hierzu und Verfahren zu ihrer Herstellung
JPS6399795A (ja) 1986-10-15 1988-05-02 Hitachi Ltd ブラシレスモ−タの位置検出回路
JPH05335068A (ja) 1992-05-28 1993-12-17 Nippon Steel Corp 誘導加熱用発振コイルの断熱材
US5416795A (en) * 1994-05-20 1995-05-16 Kaniuk; John A. Quick change crucible for vacuum melting furnace
JPH088051A (ja) 1994-06-17 1996-01-12 Nkk Corp 金属板の誘導加熱方法及び装置
JPH08288057A (ja) 1995-04-12 1996-11-01 Meidensha Corp 誘導加熱装置
EP0822733A1 (fr) 1996-08-02 1998-02-04 Selas SA Dispositif de chauffage par induction et installation de traitement thermique en continu comportant un tel dispositif
US5895599A (en) 1996-08-02 1999-04-20 Selas S.A. Induction heating device and continuous treatment installation including same
US6114675A (en) * 1997-12-05 2000-09-05 Mitsubishi Heavy Industries, Ltd. Alloying system and heating control device for high grade galvanized steel sheet
US20020168554A1 (en) * 2000-05-19 2002-11-14 Taijiro Matsui Heat insulating material having high durability, method for producing the same, use of the same, and method for applying the same
JP2005156124A (ja) 2003-11-21 2005-06-16 Hagoromo Denki Kk 誘導加熱用加熱コイルの耐熱内壁
JP2005221132A (ja) * 2004-02-05 2005-08-18 Nippon Steel Corp 誘導加熱炉の炉壁構造
JP2006169603A (ja) 2004-12-17 2006-06-29 Jfe Steel Kk 加熱設備及び加熱方法
JP2008060026A (ja) 2006-09-04 2008-03-13 Nippon Steel Corp 炉内設置型誘導加熱装置

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
European Search Report dated Apr. 26, 2013, issued in corresponding European Application No. 08833372.9.
International Search Report dated Dec. 22, 2008 issued in corresponding PCT Application No. PCT/JP2008/067992.

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KR20100055470A (ko) 2010-05-26
CA2700706A1 (en) 2009-04-02
BRPI0817676A2 (pt) 2015-03-31
RU2430164C1 (ru) 2011-09-27
BRPI0817676B1 (pt) 2016-11-08
CA2700706C (en) 2012-10-09
US20100243644A1 (en) 2010-09-30
EP2216418B1 (en) 2019-08-07
CN101809172A (zh) 2010-08-18
JP2009097080A (ja) 2009-05-07
KR101225479B1 (ko) 2013-01-22
EP2216418A4 (en) 2013-05-29
EP2216418A1 (en) 2010-08-11
WO2009041729A1 (ja) 2009-04-02
CN101809172B (zh) 2012-06-27

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